/*
 * Anything: A flexible and easy to use data structure that combines the 
 * characteristics of a list and a hashmap into one data structure.
 * 
 * Based on a paper by Peter Sommerlad and Marcel Rueedi on 
 * 'Do-it-yourself reflection' entered at EuroPLOP 1998.
 * 
 * This library was written completely from scratch and is based only 
 * in spirit on the original Java Anything implementation written by 
 * Andre Weinand/Marcel Rueedi in 1997/99 and enhanced by Stefan Tramm 
 * in 2006.
 * 
 * Copyright (c) 2008 Thomas Marti and others. All rights reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package any.functor.impl.func;

import static any.functor.Functions.asBigDecimal;

import java.math.BigDecimal;
import java.util.Iterator;

import any.ImmutableAny;
import any.functor.interfaces.Function2;
import any.functor.interfaces.NumberAnyAggregateFunction;
import any.impl.util.NumberUtils;

public class BaseNumberAnyAggregateFunction 
	extends BaseAnyIteratingAnyCreatingFunction<BigDecimal, BigDecimal, Number, BaseNumberAnyAggregateFunction> 
	implements NumberAnyAggregateFunction {

	private Function2<BigDecimal, BigDecimal, BigDecimal> aggregateFunc;

	public BaseNumberAnyAggregateFunction(Function2<BigDecimal, BigDecimal, BigDecimal> aggregateFunc, String description) {
		super(asBigDecimal(), description);
		this.aggregateFunc = aggregateFunc;
	}
	
	public BigDecimal apply(ImmutableAny from) {
		Iterator<BigDecimal> it = iterable(from).iterator();
		BigDecimal result;
		if (hasStartValue) {
			result = NumberUtils.getBigDecimal(startValue);
		} else {
			//TODO: Throw exception when empty list and no startValue??
			result = (it.hasNext() ? it.next() : null);
		}
		while (it.hasNext()) {
			result = aggregateFunc.apply(result, it.next());
		}
		
		return result;
	}

}
